In a conventional printer, printing occurs via carriage-mounted printheads which are passed across a sheet at the maximum attainable carriage velocity, generally in an attempt to maximize printer throughput by minimizing actual printing time. Carriage velocity, however, is not without boundary, or without cost. As carriage velocity increases, for example, print quality may decrease due to inherent limitations of the printhead. Also, the maximum attainable carriage velocity is governed by the carriage motor's maximum acceleration rate, and by the distance available for the carriage to accelerate.
Printer manufacturers thus have struggled to increase printer throughput by improving printhead performance, and/or by increasing attainable carriage velocity through more powerful carriage motors or increased distance for the carriage to accelerate. This approach, however, has proven to be expensive, and has sometimes required an unnecessary compromise in printer size. Further, the cited approach has failed to recognize that printer throughput is related not only to the actual printing time, but also to the carriage's acceleration and deceleration times. It will be appreciated, for example, that as the carriage's printing velocity increases, so does the amount of time it takes to accelerate and decelerate. At shorter swath lengths (the distance between an initial printing location and an initial deceleration location of the carriage), the delay due to increases in acceleration and deceleration times may, in fact, exceed any benefit from an increase in printing velocity. What is needed is a printhead carriage control approach which increases a printer's throughput by optimizing carriage velocity through a consideration of the entire carriage pass.